Folding propeller



Feb. 13, 1945'. R. L. CAMERON HAL 2,369,276

FOLDING PROPELLER Filed Aug. 20, 1943 -.1?0BE2TL. CAME/e0, 190M440 WCAMEQON,

INVENTORS.

avj z lam ATTORNEYS.

, Patented Feb. 13, 1945 Robert L. Cameron and Donald W. Cameron,

Chino, Calif.

1. Application August 20, 1943, Serial 49939 I screams. Cl.170,1 64) This invention relates to' afolding propeller. It has been primarily designed; for use in conjunction with model aircraft although it may be employed under various analogous conditions. I In model aircraft it is highly desirable to have a propeller the blades of which are capable of being folded rearwardly. The ability of the blades to fold rearwardly is desirable whenever the motor or propeller means ceases operation. Under these circumstances if the blades can fold rearwardly an effect equivalent to feathering is secured so that the blades offer no impediment to securing a long smooth glide as the model aircraft returns to earth. I

Another advantage of a propeller having rear- I wardly foldable blades is secured on landing. If

comprises a central hub structure made up of a cylindrical disk I which may have a central bore I I providing forits applicationto a propeller shaft I2. In the forward face. of this disc there are formed parallel transverse slots or grooves I 3. The

disc may be formed ofany suitable material, but

. is preferably formed of a cellulose plastic. A fitting, generally designated at I4, is appliedto the forward face of this disc.- This fitting is of channel shaped form having a central web I and parallel flanges I6 and I1, the ends of which project outwardly beyond the ends of the web. The

outer ends of these flanges areapertured as at I8 the propeller has rigid blades, one blade may en- I counter the earth on landing and may be broken or cause the model aircraft to damage itself.

With blades that are rearwardly foldable a blade on encountering the earth merely. folds rearwardly without damaging itself or causing damage to the body of the model aircraft.

A primary object of the invention is to provide a simple, but highly durable and sturdy propeller for model aircraft andthe like having a central hub structure with blades hingedly mounted thereon for rearward folding movement, and to provide an adequate strong stop means limiting forward movement of the blades into positions,

. substantially in the plane of the central hub structure whereby, during normal flight, the reactionary thrust on the blades will maintain the blades in proper position for flight purposes.

With the foregoing and other objects in view, which will be made manifest in the following detailed description and specifically. pointed out in the appended claims, reference is had to the accompanying drawing foran illustrative embodiment of the invention, wherein:

. Figure 1 is a front view in elevation of the folding propeller embodyingthe present invention; I l

Fig. 2 is a top plan view of the same, one of the blades being shown as broken away and folded rearwardly;

Fig. 3 is a sectional view taken substantially upon the line 3-3 upon Fig. 1 in the direction indicated; and

Fig. 4 is an assembly view in perspective, illustrating the elements of the central hub structure and the manner of their assembly.

I disc andthe portions 2| on the flanges I6 and I! I yond the sides of thecentral disc ID to ends of the flanges, I 6 and I1.

to receive hingepins I9. The flanges IS and I1 1 are recessed as at 20 to accommodate portions of the disc ID at the bases of the slots or grooves I3.

In assembling the central hub structure, the fitting I lis appliedto the forward faceof the which are disposed forwardly of the recesses 20 occupying the slots I3 as clearly shown in Fig. 3. The ends of the web I5 project outwardly beform stops 22, see Fig. 2', I I

The blades 23 and 24 which may be of any preferred design or configuration, have bases or roots 25 that fit between the spaced parallel ears at the They are hingedly connected thereto by means of the hinge pins I9 which are pressed into the bladesand have their ends projecting through apertures I8. The hinge, pins I9 enable the blades to be folded rearwardly as is indicatedby the blade 24 on Fig. 2. The

inner ends of the roots or bases 25 which project inwardly beyond the hinge pins I9 are en-,

gageable with the ends of the web I5, that is, they are engageable with the stops 22 to limit forward movements of the blades to positions substantially in the plane of the central hub structure. It will,

of course, be appreciated that as the hinge pins I9 are pressed into the blades and as the fitting I 4 is firmly pressed into the slots I3 that once the structure is assembled its parts are permanently united. I

Referring tothe accompanying drawing wherein similar reference characters designate similar parts throughout, the improved folding propeller During. flight the reactionary thrust on the propeller blades maintains the blades substantially in the plane of the central hub structure and in these positions the inner ends of the blades bear firmly against the stops 22. In the event that the motor discontinues operation the air stream is effective on the blades to fold them rearwardly into the positionshown by the blade 24 on Fig. 2; In this position the blades have the effect of having been feathered, thatis, they offer no impediment of the acquiring of a long,

smooth glide. In the event that the aircraft lands with the motor stopped or still in operation if the blade encounters the ground it can likewise fold rearwardly so that it will not be damaged, or cause damage to the body of the aircraft. By making the blades and the disc 10 of a cellulose I plastic a light, sturdy, and highlydurable propelleris obtained. Other materials, however,

may be employed.

Various changes'm'ay be made in the details of construction without departing from the spirit and scope of the invention as defined by the appended claims.

We claim: v 1. A folding propeller comprising a centraldisc having slots on its forward face, a channel- V shaped member having flanges positioned in the slots of the disc, the flanges'o f the channel- 1 shaped member providing ears extending outwardly therefrom, and blades hingedly mounted between the ears havinglinne'r ends engageable 95 disc.

ward face thereof, the flanges of the channelshaped member being recessed and fitting in the slots in the disc, the ears of the flanges of the channel-shaped member providing ears, blades positioned between the ears, hinge pins extending through the blades and through the ears, the

channel-shaped member providing stops engageable by the'inner ends ,of the'blades inwardly of the hinge pin to limit forward movements of the blades to substantially the plane of the disc.

3. A folding'propeller comprising means providing a central hub structure including a disc,

a channel-shaped member applicable to the forward face thereof, the flanges 'of the channelshaped member being recessed and fitting in the slots in the disc, the ears of the flanges of the channel-shaped member providing ears, blades positioned between the ears,-hinge pins extending through the blades and through the ears, the channeleshaped member having a web, the ends of which project outwardly beyond the sides of the disc providing stops engage'able by the inner ends of the blades to limit forward movements of the. blades to substantially the 'plane of the ROBERT LfonMEaoN. 1301mm W. iCAMERONt 

